Hello! Look! See there!" Far away out on the plain Hugh saw fifteen or twenty bluish-grey mounds in a line rising above the grass; it was a herd of buffalo feeding.
The animals never lifted their heads, and were curiously like a lot of railway trucks covered with grey tarpaulin.

It was impossible to tell which was head and which was tail.

A short halt was made while girths were tightened, cartridges slipped into place, and hats jammed on; they all mounted and rode slowly towards the herd, which was at least half a mile off, and still feeding steadily.

Everyone kept his horse in hand, ready for a dash the moment the mob lifted their heads.
"How fast will they go ?" whispered Hugh to the nearest shooter.
"Fast as blazes.

You've no idea how fast they are.